I'm no category expert. In fact I'm so confused about the National and International Days that I am reluctant even to give feedback. But I would like GCU to at least get my concept. I may do this clumsily so be patient.
 
I would like to see a separation of cards that an organization (business) would give to employees or contractors and those that the main public would give for National and International Days. My past sales data indicate that organizations purchase these "occupational proclamations". What I term occupational proclamations are what GCU terms as Holidays - as a recent example: National Physician Assistants Day.  Currently organizations have to  wade through general cards which include "to my. . ." and other cards that a consumer of services would give to their service provider.  
 
Currently there are 2 categories where the National and International cards are located:
Holidays and Collections > National and International Days. But not all industry specific holidays can be found in the Collections. Through my research I discovered that by USA federal government definition these are not true holidays. In fact Occupational Proclamations are so abundant that they cover a broad range of hobbies, activities as well as industries. Here is a link to all of the current USA National Proclamations: http://www.whitehouse.gov/briefing-room/presidential-actions/proclamations. This doesn't even include International Days.
 
I believe that by creating categories that target organizations and businesses for these trade days it will increase the potential for larger orders.  Especially in the medical industry.  There are many avenues to implement to achieve this goal. If someone forced my hand to make a suggestion it would be to add the appropriate category to the existing: Business > Industry Specific. After all, they usually are industry specific.
 
However, I'll let the keeper of master categories mull this over. This is not an easy taxonomy decision to make.